345b7a8757
Division may (optionally) raise a division exception. Since the linux kernel has been prepared for this for some time, enable it by default. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20220421151735.31996-42-richard.henderson@linaro.org>
80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/*
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* Altera Nios II helper routines.
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*
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* Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see
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* <http://www.gnu.org/licenses/lgpl-2.1.html>
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "exec/helper-proto.h"
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#include "exec/exec-all.h"
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#include "qemu/main-loop.h"
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void helper_raise_exception(CPUNios2State *env, uint32_t index)
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{
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CPUState *cs = env_cpu(env);
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cs->exception_index = index;
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cpu_loop_exit(cs);
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}
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static void maybe_raise_div(CPUNios2State *env, uintptr_t ra)
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{
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Nios2CPU *cpu = env_archcpu(env);
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CPUState *cs = env_cpu(env);
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if (cpu->diverr_present) {
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cs->exception_index = EXCP_DIV;
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cpu_loop_exit_restore(cs, ra);
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}
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}
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int32_t helper_divs(CPUNios2State *env, int32_t num, int32_t den)
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{
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if (unlikely(den == 0) || unlikely(den == -1 && num == INT32_MIN)) {
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maybe_raise_div(env, GETPC());
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return num; /* undefined */
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}
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return num / den;
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}
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uint32_t helper_divu(CPUNios2State *env, uint32_t num, uint32_t den)
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{
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if (unlikely(den == 0)) {
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maybe_raise_div(env, GETPC());
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return num; /* undefined */
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}
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return num / den;
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}
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#ifndef CONFIG_USER_ONLY
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void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc)
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{
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Nios2CPU *cpu = env_archcpu(env);
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/*
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* Both estatus and bstatus have no constraints on write;
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* do not allow reserved fields in status to be set.
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* TODO: more than this is required for shadow registers.
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*/
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new_status &= cpu->cr_state[CR_STATUS].writable;
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env->ctrl[CR_STATUS] = new_status;
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env->pc = new_pc;
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cpu_loop_exit(env_cpu(env));
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}
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#endif /* !CONFIG_USER_ONLY */
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